Wellhead apparatus utilizing casing deforming slips to suspend the casing



May 26, 1964 R. c. BROOKS 3,134,614

WELLHEAD APPARATUS UTILIZING CASING DEFORMING SLIPS TO SUSPEND THE CASING Filed June 28. 1961 2 Sheets-Sheet 1 a gmimiii INVENTOR.

y 26, 1954 R. c. BROOKS 3,134,614

WELLHEAD APPARATUS UTILIZI CASIN EFORMING SLIPS TO SUSPEND CASI Filed June 28, 1961 2 Sheets-Sheet 2 L 36 J6 W Faber! C fi/oakJ INVEN TOR.

United States Patent Ofifice 3,134,614 Patented May 26, 1964 3,134,614 WELLHEAD APPARATUS UTILIZING CASING DEFORMING SLlPS TO SUSPEND THE CASING Robert C. Brooks, Houston, Tera, assignor to Cameron Iron Works, Inc, Houston, Tex., a corporation of Texas Filed June 28, 1961, Ser. No. 120,332 3 Claims. (Cl. 285--144) This invention relates in general to apparatus for use in completing multiple zone wells through side-by-side tubing strings suspended within a casing at the wellhead. In one of its aspects, it relates to an improved hanger for suspending the casing Within such a wellhead.

In the completion of such wells, it is desirable to dispose the tubing strings as close together as possible since this reduces the size of the casing and easing head required and generally the cost of drilling the hole. Although the tubing strings may extend within the casing as close together as their couplings permit, a greater spacing therebetween is required by the passages through the master valve to which such strings are connected above the casing head. Consequently, it has heretofore been necessary to provide either over-sized casing or one or more enlarged joints on the upper end of the casing which permit the tubing strings to be spread apart sufficiently to connect with the master valve.

Further, an operator may decide, during the completion of a Well, to produce it from one more zone than originally planned. Although the additional tubing string may extend within the casing along with the other strings originally planned, the additional master valve passage requires greater spacing between such strings. Thus, the operator ordinarily must either use larger casing or otherwise improvise to enable the tubing strings to be connected with the passages in the master valve.

An object of this invention is to provide apparatus, and particularly a casing hanger, which avoids the need for over-sized casing;

Another object is to provide apparatus including a casing hanger which permits the operator to complete a well through a greater number of tubing strings than originally planned.

A further object is to provide a hanger for suspending ordinary casing in such a manner that the tubing strings may be spread apart therein for connection with the master valve; and, more particularly, a casing hanger of such construction that it will deform a cylindrical casing into a shape for accommodating spread-apart tubing strings merely in response to suspension of said casing therefrom These and other objects are accomplished, in accordance with the illustrated embodiments of this invention, by a Wellhead in which the upper end of the casing string and the hanger thereabout have portions which are radially enlarged to accommodate spreading of the tubing strings from side-by-side positions within the casing below its enlarged portions to connection with the master valve. In accordance with the preferred embodiments of the invention, the casing hanger comprises a plurality of arcuate slip segments adapted to be arranged in circumferentially spaced-apart relation in the annular space between the casing and the bore of the casing head. As in the conventional slip type hangers, these segments have outer surfaces which are conically shaped for sliding downwardly and inwardly along a seat in the head into gripping relation with the casing.

However, as distinguished from conventional hangers, the alternate wedge segments are radially thicker and thinner than ordinary segments for this size of casing and having casing gripping surfaces curved about radii which are larger and smaller, respectively, than the radius of the casing. Thus, as the load of the casing is transferred thereto, the thicker segments having inner surfaces curved on the larger radius will deform the adjacent portion of the casing radially inwardly, while the thinner segments having inner surfaces curved on the smaller radius will permit the casing to expand radially outwardly corresponding amounts. As noted above, the thusly formed radially enlarged portions on the inside of the casing permit the tubing strings extending therethrough to be spread out sufficiently to connect with the master valve.

A number of pairs of alternate slip segments, and thus the number of enlarged portions to be formed in the casing, will of course equal the number of tubing strings to be suspended within the casing. Thus, for example, a hanger for a casing through which two strings are to extend will have four slip segments, a hanger for a casing to accommodate three strings will have six slip segments, etc.

In the drawings, wherein like reference characters are used throughout to designate like parts:

FIG. 1 is a vertical sectional view of a wellhead including a casing head having a casing suspended therein by means of a hanger constructed in accordance with the present invention, and with a pair of tubing strings extending through such casing for connection with the lower end of a master valve;

FIG. 2 is an enlarged cross-sectional view of part of the Wellhead of FIG. 1, as seen along broken line 3-3 thereof prior to the disposal of the casing hanger therein;

FIG. 3 is another cross-sectional view of the wellhead, again as seen along broken line 3-3 of FIG. 1, but with the hanger disposed therein for suspending the casing therefrom;

FIG. 4 is an enlarged View of another embodiment of a casing hanger constructed in accordance with the present invention, and particularly one for suspending a casing through which three tubing strings extend; and

FIG. 5 is a view similar to FIG. 4 of still a further embodiment of the invention wherein the hanger suspends a casing through which four strings of tubing extend.

With reference now to the details of the above-described drawings, the wellhead 10 shown in FIG, 1 includes a casing head 11 connected to the upper end of an outer casing 12. An inner casing 13 is suspended within the outer casing 12 and the bore 14 through the casing head 11 by means of the casing hanger 15 supported upon a seat 16 at the upper end of the bore. A tubing head 17 is connected above the casing head 11 by means of bolts 18 or thelike and has a bore 19 therethrough forming a continuation of the bore through the casing head. The two heads are sealed with respect to one another by means of an annular seal ring 20 therebetween, and a pair of tubing hangers 21 are supported within the bore 19 of the tubing head to suspend apair of tubing strings 22 therefrom in side-by-side relation. As shown in FIG. 1, and as will be described more fully hereinafter, the tubing stringsextend downwardly from their hangers 21 within the inner casing 13 for communication with different productionzones within the well. The tubing hangers 21 are supported within the tubing head by any suitable means such as that shown in US. Patent No. 2,794,505.

A master valve 23 is connected above the tubing head by means of bolts 24 or the like and is sealed with respect thereto by means of an annular seal ring 25. This master valve has a pair of side-by-side passages 23a extending therethrough separately connecting at their lower ends with the tubing hangers 21. More particularly, and as shown in the aforementioned patent, the lower ends of the passages 23a are provided with tubular enlargements for fitting closely about tubular upper extensions on the tubing hangers 21, and suitable seal means is disposed therebetween to insure the separate connection of each tubing string with its master valve passage.

As previously mentioned, the tubing strings 22 may extend through the inner casing 13 as closely as their couplings (not shown) permit to enable the operator to use a casing of the least possible size. However, and as also mentioned above, the center lines through the passages 23:! of the master valve 23 cannot be disposed this close together, principally because of the peculiar construction of a master valve which requires the disposal of a separate valve member across each side-by-side passage. Thus, in order to take full advantage of the smallest possible casing, and thus the least expensive drilling costs, the operator must somehow enable the tubing strings to be spread apart from within the casing to their connection with the master valve. As can be seen from FIG. 1, this spreading of the tubing strings must be accomplished within a relatively short vertical distance. In fact, and as previously mentioned, it has not been heretofore found possible to so spread the tubing strings without larger diameter casing at the upper end of the casing string.

As shown in FIGS. 1 and 2, and as well known in the art, the seat 16 in the upper end of the bore 14 of the casing head 11 is conical and tapers downwardly and inwardly. The casing hanger within the annular space between the casing 13 and the bore of the casing head is preferably of the well known wrap-around type which permits its disposal within such annular space while the casing 13 is otherwise suspended within the head. After the hanger 15 is latched about the casing and lowered onto the seat 16, and the weight of such casing is lowered onto the hanger to permit its suspension therefrom, the upper end of the casing is cut off, as shown in FIG. 1, and the remainder of the previously described wellhead is installed thereabove in a manner well known in the art.

In any case, the hanger 15 comprises a plurality of circumferentially spaced-apart, arcuate slip segments 26 each having a conical outer surface 27 for sliding downwardly and inwardly along the seat 16 and a cylindrical inner surface having teeth 28 for gripping the casing. In the embodiment shown in FIGS. 1 and 3, each slip segment 26 is suspended from a sealing assembly 29 by means of bolts 30 extending through such assembly and connected at their lower ends to each such segment. As is conventional in the art, the sealing assembly 29 includes a lower compression member 31 disposed above the slip segments, a seal ring 32 disposed above the member 31, and an upper compression member 33 disposed above the seal ring and connected to the upper ends of the bolts 30.

As is the case in other hangers of this general type, the seal ring 32 extends across the annular space above the slip segments and between the casing and bore of the casing head for sealing therebetween as the upper compression member 33 is compressed thereagainst upon manipulation of the bolts 30. The compression members 31 and 33 as well as the seal ring 32 are split at any desired location to permit the entire hanger to be opened and closed for latching about the casing 13. In this type of construction, the seal ring acts as a hinge in permitting the separate halves of the hanger to pivot for opening and closing. Also, as best shown in the cutaway portion of FIG. 3, the adjacent slip segments are connected to one another for movement vertically together by means of small plates 34 or other suitable means extending within recesses 35 therebetween. As is also well known in the art, the hanger 15 is oriented in a rotational sense within the head 11 by means of a slot in one of the slip segments adapted to fit over an aligning pin 16a in the bowl of the head. Thus, upon bolting of the tubing head 17 above the casing head, suitable aligning parts in the former (such as shown in the aforementioned Patent No. 2,794,505) will be disposed for supporting the hangers 21 with the tubings 22 suspended therefrom adjacent the enlarged portions of the casing.

The circumferentially spaced-apart suspension of the slip segments permits them to move downwardly and inwardly into gripping engagement with the casing 13 as the 4 outer conical surfaces 27 are seated upon seat 16 in the casing head. Thus, as shown in FIG. 3, there will ordinarily be at least a slight space between the slip segments 26 even after they have gripped and suspended the casing.

As indicated by the broken lines 13a of FIG. 3, the portion of the casing 13 adjacent the hanger 15 is originally of the same cylindrical shape as the lower portion thereof. However, and as will be described more fully hereinafter, the hanger segments 26 are of such construction that the casing is deformed into a substantially elliptical shape, as shown by the solid lines of FIG. 2. Thus, the inside of the casing 13 is enlarged or widened along one axis, while being reduced in width or shortened along a transverse axis. This radial enlargement of the casing enables the two tubing strings 22 disposed therein to be spread apart from a location beneath the casing hanger to their connection with the master valve 23. Thus, as best shown in FIG. 1, the deformation of the casing resulting from its suspension from the casing hanger 15 is gradual from its maximum extent opposite the slip segments of the hanger to a point therebelow.

This enlargement of the casing 13 is only that sufficient to accommodate this spreading apart of the tubing strings 22 necessary to permit their connection with the master valve. Thus, there is no more inward deformation of the casing than necessary. Ordinarily, it would be expected that the inward deformation would correspond to and be no greater than the radial enlargement of the casing. This insures that there is sulficient space across the now short axis of the casing to pass packers as well as other tools which must be run through the casing.

As previously mentioned, and again as best shown in FIG. 3, alternate ones of the slip segments of the hanger 15 are radially thickened intermediate their opposite end edges and have inner surfaces 26a curved on a radius larger than that of the normally cylindrical casing 13 (shown in broken lines). On the other hand, the other intermediate slip segments are radially thinned intermediate their opposite end edges and have inner surfaces 261) which are curved on a smaller radius than that of the cylindrical casing 13. Thus, with the conical surface 27 of each slip segment curved about an axis at least substantially coinciding with the axis of the casing 13, the axis of each surface 26a will be disposed with respect thereto radially outwardly of the axis of the conical surface, while the axis of each surface 2612 will be disposed radially inwardly of the axis of the conical surface. This method of approximating an ellipse by circular arcs of two difierent radii is well known to those skilled in the art and is given, for example, on page 139 of Marks Mechanical Engineers Handbook, fifth edition.

As will be understood from FIG. 3, when the hanger is first wrapped about the casing and lowered onto the seat 16, and the weight of the casing is lowered onto the slip segments of the hanger, the middle portions of the inner surfaces 26a will initially grip the casing. As they accept the load of the casing, the surfaces 26a will move downwardly and thereby begin to deform the upper and lower portions of the cylindrical casing radially inwardly. This, of course, results in a corresponding radial outward deformation of the opposite sides of the casing. As will be understood, however, these opposite sides of the casing are free to be deformed in this manner since the inner surfaces 26b have not yet moved downwardly into engagement therewith. This inward deformation of the casing continues until such time that the radially outwardly deformed portions thereof move into engagement with the inner surfaces of segments 26b. At this time, and as shown in FIG. 3, the entire inner surfaces 26a and 26b will ordinarily have gripped the casing so that the casing is gripped about its entire circumference.

As previously mentioned, the hanger 15 is made up of four segments with the inner surfaces 26a and 26b disposed in oppositely facing pairs, with each pair producing an enlarged and a corresponding reduced portion on the casing. More particularly, the inner surfaces of adjacent slip segments have inner surfaces which are curved on different radii, the extent of such difference depending, of course, on the desired degree of deformation of the casing.

Thus, for example, operators have heretofore found it necessary to use a light weight 5 /2" O.D. casing having a 4.892" ID. in which to suspend a pair of 2 O.D. tubing strings. However, with a hanger 15 constructed in accordance with my invention, a heavier 5 /2" O.D. casing having a 4.670" LD. may be used for this purpose. In such a case, the surfaces 26a may be curved about a 3 radius and the surfaces 26b about a 2 /2" radius, each being A" larger and smaller, respectively, than that of the 5 /2 casing.

As shown in FIG. 4, the casing hanger 35 suspending the casing 37 through which three tubing strings 38 extend comprises six slip segments 36 arranged in circumferentially spaced-apart relation. These slip segments may be suspended from a sealing assembly and connected to one another for movement downwardly within a casing head bore similar to the segments 26. Also, of course, one of the segments may be slotted for alrigning purposes. As was further the case of the hanger 15, alternate slip segments are radially thickened and have inner surfaces 36a curved on a larger radius than the radius of the originally cylindrical shape 37a of the casing 37, and the segments therebetween are radially thinned and have inner surfaces 3612 which are curved on a smaller radius than that of the cylindrical casing. Thus, in suspending the casing 37, the slip segments of the hanger 35 will deform it into three radially enlarged portions to accommodate the spread-apart tubing strings 38. As can be seen from FIG. 4, these enlarged portions of the casing are substantially equally angularly spaced about the axis thereof, although, as distinguished from the casing 15, there is a radially enlarged portion opposite each radially reduced portion.

As shown in FIG. 5, the casing hanger 45 suspends a casing 46 in a manner to receive four spaced-apart tubing strings 47. Thus, there are eight slip segments 48, with alternate segments each being radially thickened and having an inner surface 48a curved on a radius larger than that of the original cylindrical shape 46a of the casing and the segments therebetween having inner surfaces 48b which are radially thinned and curved on a smaller radius than that of the cylindrical casing. Thus, the suspension of the casing 46 from the hanger 45 deforms it radially outwardly at four substantially equally angularly spaced-apart locations to accommodate the spaced-apart tubing strings 47. Inasmuch as there are an even number of tubing strings 47 to be received within the casing 46, the inner surfaces 48a as well as the inner surfaces 48b are disposed in diametrically opposed pairs. As in the casing of the other hangers, the hanger 45 may be provided with suitable means for orienting it within a casing head.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope hereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described what is claimed is:

1. A wellhead, comprising a casing head, a tubing head connected above the casing head, a slip type casing hanger in the casing head suspending a casing therefrom, and tubing hangers supported in the tubing head suspending tubings therefrom in side-by-side relation within the casing, the slips of the casing hanger having inner radially enlarged portions corresponding in number to the tubings suspended therein and the upper end of the casing being deformed by the inner radially enlarged portions of the casing hanger slips into correspondingly enlarged portions, each tubing being disposed substantially adjacent an enlarged portion of the casing and spread apart from a point in the casing below the enlarged portions thereof to connection with a tubing hanger.

2. A casing hanger adapted to be seated on a conical bowl within the bore of a casing head, comprising a plurality of slip segments arranged in circumferentially spaced-apart relation, the outer seating surface of each segment being conically shaped for sliding along said bowl, and the inner casing gripping surface of alternate segments being curved to a smaller radius than the inner surfaces of the segments therebetween, said gripping surface of each segment forming a substantial continuation of the gripping surfaces of adjacent segments.

3. A casing hanger adapted to be seated on a conical bowl within the bore of a casing head, comprising a plurality of arcuate slip segments disposed in circumferentially spaced-apart relation to form an annular body, said plurality of segments providing an outer conical surface for sliding along the bowl of the casing head, the inner casing gripping surfaces of adjacent segments being curved about axes offset radially inwardly and outwardly, respectively, of the axis of the outer conical surface thereof to provide an opening through the hanger which is substantially elliptical in transverse cross section.

References Cited in the file of this patent UNITED STATES PATENTS 1,761,521 Eastman June 3, 1930 2,335,355 Penick Nov. 30, 1943 2,864,161 Curtiss Dec. 16, 1958 2,874,436 Allen Feb. 24, 1959 

1. A WELLHEAD, COMPRISING A CASING HEAD, A TUBING HEAD CONNECTED ABOVE THE CASING HEAD, A SLIP TYPE CASING HANGER IN THE CASING HEAD SUSPENDING A CASING THEREFROM, AND TUBING HANGERS SUPPORTED IN THE TUBING HEAD SUSPENDING TUBINGS THEREFROM IN SIDE-BY-SIDE RELATION WITHIN THE CASING, THE SLIPS OF THE CASING HANGER HAVING INNER RADIALLY ENLARGED PORTIONS CORRESPONDING IN NUMBER TO THE TUBINGS SUSPENDED THEREIN AND THE UPPER END OF THE CASING BEING DEFORMED BY THE INNER RADIALLY ENLARGED PORTIONS OF THE CASING HANGER SLIPS INTO CORRESPONDINGLY ENLARGED PORTIONS, EACH TUBING BEING DISPOSED SUBSTANTIALLY ADJACENT AN ENLARGED PORTION OF THE CASING AND SPREAD APART FROM A POINT IN THE CASING BELOW THE 